---
layout: docs
page_title: Common Issues - Disks VirtualBox Provider
sidebar_title: Common Issues
description: |-
  This page lists some common issues people run into with Vagrant and VirtualBox
  as well as solutions for those issues.
---

# Common Issues and Troubleshooting

This page lists some common issues people run into with Vagrant and VirtualBox
as well as solutions for those issues.

## Are my disks attached?

A handy way to figure out what disks are attached (or not attached) to your guest
is to open up the VirtualBox GUI and select the guest. When selecting a guest on the GUI,
it should open more information about the guest, including storage information. Here
you should see a list of disks attached to your guest.

## How many disks can I attach?

Vagrant attaches all new disks defined to guest's primary controller. As of
VirtualBox 6.1.x, storage controllers have the following limits to the number
of disks that are supported per guest:

- IDE Controllers: 4
- SATA Controllers: 30
- SCSI Controllers: 16

Therefore if your primary disk is attached to a SATA Controller and you try to
define and attach more than 30, it will result in an error. This number
_includes_ the primary disk for the guest.

DVD attachments are subject to the same limits.  Optical disk attachments will
be attached to the storage controller with the highest boot priority (usually
the IDE controller).

## Resizing VMDK format disks

VMDK disks cannot be resized in their current state, so Vagrant will automatically
convert these disks to VDI, resize the disk, and convert it back to its original format.
Many Vagrant boxes default to using the VMDK disk format, so resizing disks for
many users will require Vagrant to convert these disks. Generally, this will be transparent
to the user. However if Vagrant crashes or if a user interrupts Vagrant during the
cloning process, there is a chance that you might lose your data.

## Applying Vagrant disk configuration changes to guests

Due to how VirtualBox works, you must reload your guest for any disk config changes
to be applied. So if you update your Vagrantfile to update or even remove disks, make
sure to `vagrant reload` your guests for these changes to be applied.
